I've been trying to make a schematic for a possible LED display, it involves a 74HC595 shift register and a 4017 decade counter to make images using persistence of vision. It's not clear in the picture but I'll use 68 Ohms resistors. My question is will this work and do I need resistors for the transistor?
P.s. It's my first time using fritzing so advice would be helpfull
Not bad for a fritzing schematic, from posts we have seen I didn’t even think that was possible.
The 4017 symbol is crap, can’t tell what the different pins are.
You also need a 0.1uF cap to Gnd on the Vcc pin of each device.
Anyway, the design won’t work. LEDs in series like that will need 12-15V to turn them all on. 74HC595 cannot supply that.
If you have a 12V to 15V source, you can use the '595 to drive NPN transistors that can pull the base of PNP transistors low to source current into the LED anodes.
This part would do great with a 12V supply.
Can source 24mA, Vout will be at least 11V.
No clock or latch needed, data is detected off the Data pin, at a slow 24Kbps rate, so something a little different would need to be written up to send the data out.
I don't know why I can't find an open source shift register.
Two more questions, one Fritzing isn't working for me any other CADs you guys recommend that are completely free(I tried KiCAD but the component's pinouts are wrong, or maybe I'm using the wrong packages for the components). And two, why don't the pinouts on a CD4017b(Texas Instruments) come in order like 0 at the top and 9 at the bottom of the same side. Doesn't that make it much easier to use?